Purpose: Functional imaging by standard whole-body (WB) 18F-flurodeoxyglucose (FDG) positron emission tomography (PET) is an integrated part of disease diagnostics. Recently, a clinical dynamic whole-body (D-WB) FDG PET/CT scanning protocols has been developed allowing for quantitative imaging of tissue metabolic rate of FDG (MRFDG). It was the purpose of this retrospective study to evaluate whether MRFDG imaging is feasible in a clinical setting and whether it improves lesion detectability.
Methods: One hundred nine patients representing a broad range of referral indications for FDG PET/CT were invited to undergo a D-WB FDG PET/CT scan. Two sets of images were produced: parametric images and standard static SUV images. Both sets of images were reviewed visually, and 310 individual lesions were quantitatively analysed using the target-to-background (TBR) and contrast-to-noise (CNR) metrics.
Results: One hundred three out of 109 patients completed the D-WB FDG PET/CT scan. There was no difference in the number of pathological lesions identified visually on the MRFDG and the SUV images, whereas MRFDG images yielded 4 fewer false positives than the SUV images. Quantitatively, MRFDG TBR was significantly higher than SUV TBR in 299/310 lesions, and better MRFDG CNR was found to facilitate the challenging reading of lesions with low SUV TBR.
Conclusion: D-WB FDG PET/CT is feasible in a clinical setting and produces MRFDG images of good visual quality and superior lesion contrast. In addition, MRFDG images complement the standard SUV images providing better quantification and enhanced image reading. However, although MRFDG also reduced the number of false-positive findings, no additional malignant lesions were identified. The technique therefore appears to be best suited for select patient groups or possibly treatment response evaluation.
Keywords: Clinical; Dynamic whole-body PET; FDG; Oncology; Parametric imaging; Patlak.